For years..this has eluded me!!!!
406 saloon,2004
I have always had gremlins with the electrical block in the drivers footwell and carpet soaking all the time so for years,I have been trying to trace a frontal leak.
Had the car at mot last night which it passed and only the other day,I noticed water under the back seat so turned my attention to the rear.
Stripped the boot of its trim and parked on a hill with nose down and since im in NI...no shortfall of rain today!
I can see water coming in around the boot seal and under the parcel shelf...in quite a high volume!
Tailights seem to be water tight as that was suspected.
anyone seen this problem?
I suspect my bootseal and possible rear window leak.
Next step is to remove the parcel shelf and have a look

There is a thread on the KB, where the join on the actual bodywork behind the rear bumper was where the water was getting in......
I guess you haven't got a sunroof...??

1999 T4 family wagon, slow as a turd but the kids like it2002 Citroen Xsara Picasso Hdi90 - Dirtied by the kids, Dented by the wife....Sadly sold the 406, best cars I have ever ownedPP2000 user, can help with faults / diagnostics in the Bournemouth area.

Solid roof,no sunroof in this baby.
Well,think I have cured it.
If a 406 saloon sits on a hill with nose down(My drive at home is all downhill with no level)the pockets on the boot shut really fill with water,just at the bottom corners of the back window(saloon shape).
Had the rear shelf out,hole in window bonder,bottom drivers corner so got in with silcone gun and sealed it.
2nd leak,just at the corners of the rubber at boot hinges,both sides.Water creeping through between bodywork on the boot opening lip and rubber.
Took off the seal,silconed around the corners on the boot lip and refitted seal,seems to have cured it.
Will leave it tonight with newspaper on boot floor,guaranteed rain here tonight for the test